Crossrail – the engineering geology

For those outside the UK, the Crossrail project is a mega-project upgrade to the London metro area’s subway system. The tunneling portion of the project will consist of 21-km of twin-bore tunnels excavated by eight closed-faced tunnel boring machines, six of which will be earth pressure balance machines (EPBMs). The UK’s Geological Society has published an interesting article on the geology of the crossrail project. Some of the geological and geotechnical challenges of the project include the famous London Clay, sensitive structures, faults, and rapid transitions between permeable and relatively impermeable formations creating potential water pressure issues. [Source: Geological Society. Image: Geological Society]

A stretch of tunnel on Eastbound I-70 in scenic Glenwood Canyon Colorado was closed last March because of a 70-foot long crack in the ceiling. Since then the two-lane westbound bore has been handling both eastbound and westbound traffic while repairs to the damaged segment were undertaken. This project has a little of everything: heavy excavation, rockfall, slab reinforcing, geofoam, and even geogrid! Read on for more details, a map and photos. (Photo by Concrete Works Of Colorado)

On the island nation of Singapore land is at a premium, so a planned petrochemical storage facility is being constructed 150 meters under the sea floor. The article does not give the total underground storage […]